1. Field of the Invention
This invention relates generally to semiconductor chip manufacturing, and more particularly to apparatus and methods of providing regulated voltage to semiconductor chips.
2. Description of the Related Art
Desktop computers, servers and related equipment frequently use a main circuit board or “motherboard” to house many types of internal electronic components. Such components include, for example, a central processing unit (CPU), one or more slots or sockets to receive various types of cards, various input/output ports and other devices. In addition to a CPU, one component that is commonly placed on the motherboard is a voltage regulator. A typical voltage regulator receives one or more input voltages from a system power supply and provides a regulated output voltage that is used by one or more components on the motherboard. In one example of a common operation by a conventional voltage regulator, a 12 volt power output from a system power supply is converted to a regulated low voltage output in the 0.3 to 3.3 volt range for use by a microprocessor.
Conventional voltage regulators normally consist of an integrated circuit that provides the voltage regulation function as well as one or more inductors and some additional logic, such as a field effect transistor, as necessary to facilitate the voltage regulation function. These various components are usually all positioned on the motherboard.
Although the placement of the voltage regulator on the motherboard is superficially attractive from a manufacturing standpoint, there are nevertheless several drawbacks associated with such an arrangement. To begin with, placing the voltage regulator on the motherboard takes up space which might otherwise be used for other components. In addition, the voltage regulator is a source of heat that is transferred to the motherboard, which can create certain reliability issues with regard to the life span of the motherboard. Many configurations of motherboards do not receive sufficient air flow from a CPU cooling fan that might otherwise provide adequate cooling of the voltage regulator heat load. In addition, the way in which the on-motherboard voltage regulator delivers power to the microprocessor creates certain issues with regard to manufacturing and cost. For example, conventional microprocessors may require several hundred pins, many of which are dedicated to providing a power and ground pathway between the microprocessor and the voltage regulator output. This relatively large number of pins dedicated to power and ground increases the cost of the microprocessor socket. Another problem associated with the conventional wiring between the onboard voltage regulator and the microprocessor is the fact that conventional motherboards must have relatively heavy copper layers in order to handle the current load of the microprocessor. Finally, conventional motherboards with dedicated onboard voltage regulators have relatively limited capacity to deal with voltage regulator upgrades that might be appropriate in circumstances where the power ratings of microprocessors increase. This latter factor is one of the principle reasons why motherboards tend to go out of date rather quickly.
One conventional alternative approach to an on-motherboard voltage regulator involved the use of a voltage regulator module designed to be positioned in between the microprocessor lid and an overlying heat sink. The module included a voltage regulator integrated circuit and an inductor as is commonly utilized in an on-motherboard voltage regulator as well as one or more connectors designed to provide an electrical pathway between the regulator module and contact pads on the substrate of the microprocessor package. This conventional system suffered from a couple of drawbacks. To begin with, the system involved the assembly of several components that required relatively precise vertical and horizontal alignment in order to function properly. This requirement for precise alignment could lead to installation and performance problems, particularly for inexperienced users. In addition, the fact that the voltage regulator module was inserted into the stack consisting of the heat sink and the underlying microprocessor package meant that the regulator would contribute heat to that stack that could easily overload the cooling capacity of the heat sink. Furthermore, the heat from the microprocessor itself could tend to degrade the life span of the regulator board due to the significant conductive heat transfer pathway from the microprocessor package.
The present invention is directed to overcoming or reducing the effects of one or more of the foregoing disadvantages.